Just getting opinions but from other posts on this forum, I think I found my match in Cf/cs with Forticlient AV Free.
I agree too many installs and uninstalls leave remnants, and I do have multiple system images as backups. Thanks.
If I'll pick based on what you enumerated, then I would recommend going with ESET if you want minimal impact with good protection. There are other AVs that are good too such as F-Secure and Webroot. Kaspersky does give a great protection but depending on your PC it can be a security with minimal impact or as heavy as Bitdefender or even worse as heavy as Trend Micro.
It can be run standalone in a single pc but has applications to run with their specific hardwares. More info can be gleaned from their website, and Slyguy's hardening suggestion on this website. Hope this helps